Alloy



Patented May 20, 1941 ALLOY Erich Fetz, Newark, N. .L, assignor to Wilbur B.

Driver 00., Newark, N. J

., a corporation of New Jersey No Drawing. Application October 19, 1938,-

' Serial No. 235,786

4 Claims. ('01. 75-134) The invention relates to alloys and more particularly to alloys for electrical resistance uses.

In the patent to Wilbur B. Driver #943,066 granted December 4, 1909, there is disclosedan alloy containing manganese and nickel inthe order of 540% of manganese and 50% or more of nickel. Similarly, in the patent to Driver and Keith #1,803,467, an electrical resistance alloy with a nickel. chromium and nickelchromium-iron base was disclosed. Additions of manganese and manganese and vanadium were employed to increase the ohmic resistance of the product but it was found that brittleness and hardness increased in almost the same degree as did the resistance, thus presenting serious manufacturing difliculties, particularly in the final or cold working of the product.

The present invention relates to an alloy of high ohmic resistance characterized by a greatly improved degree of workability and ductility as compared with the Driver and Driver, Keith disclosures.

For example, it was found that a nickelmanganese alloy of approximately equal proportions of nickel and manganese and diluted with of ironcould be worked very readily and has a resistance of 914 ohms/emf. Furthermore, it was discovered that by replacing 1% of iron by 1% of aluminum, the resistance of the alloy was increased to 980 ohms/emf. The physical properties of this latter alloy in the annealed state were, as follows:

Tensile strength 92,300 lbs./in. Elongation, percent/3 in 32.5%

Tensile Elongation, strength percent/3 in. eslstance lb./sq. in. st length ohms/c Hard drawn"; 167, 000 3 957 Annealed 99, 400 45 1035 1 From a mechanical viewpoint the combination of strength and ductility of my alloys compares favorably with that of alloys in general and greatly surpasses the corresponding qualities of high electrical resistance alloys with which I am acquainted. It will additionally be noted that although electrical resistance and brittleness are inter-related in accordance with the present state of scientific knowledge of the physical properties of such materials, yet my alloys demonstrate the phenomenon of increased resistivity without a corresponding increase in brittleness.

Yet another departure from accepted theory has been observed in the drawing of wire formed from thepresent alloys More particularly, it

is well known that the finest wire gauges suffer a certain loss of electrical resistance in the drawing of wires from nickel, nickel-copper and nickel-iron-copper and iron-copper! aluminum base alloys; the peculiarity being ascribed to a skin effect, Careful tests indicated that this resistance drop did not appear in my manganesenickel base alloys when drawn to wires of the finest sizes. For example, an alloy containing nickel, 35% manganese, 15% iron and 15% copper was drawn down without di fliculty to the .00 in. sizes and the following resistances were determined:

An additional observed feature of my alloy is its insusceptibility to the temperatures commonly employed in enameling processes. Thus, when subjected to temperatures of approximately 600 F. during an enameling operation, the physical properties of alloys of nickel-manganese and. to any noticeable extent. 4

Although I' have specifically described the properties of alloys of nickel-manganese and iron and nickel-manganese-copper and iron, I have found by exhaustive tests that a basic nickel-manganese alloy in the proportions-of 40 of nickel to of manganese may be diluted with additions of cobalt, chromium and copper to produce desirable results. The following test data illustrate the effect upon the basic binary alloy of varying proportions of chromium, cobalt and copper:

Electricalresistance in ohms/c. m, f.

M Nickel 32% Iron Cobalt Copper gaeeeeeeegs eeeeeae manganese, 10 to 15% copper and the balance iron.

2. electrical resistance alloy consisting essentially of 40% nickel, 40% manganese, 15%

4. -An electrical resistance alloy characterized byia resistivity of substantially 1000 ohms-cmL, and containing substantially 40 per cent of nickel, 40 per cent of manganese, 10 per cent of 5 copper, and 10 per cent of iron.

ERICH FE'IZ. 

